This invention relates to the generation of ozone, and is particularly directed to devices that emit ultraviolet light to convert atmospheric oxygen to ozone in air that flows therethrough.
Ozone is used in the home or workplace because of its ability to react with many noxious or objectionable vapors and remove them from the environment. Ozone is also poisonous to many types of fungus, yeast and bacteria, and can be used to control decay causing organisms in food substances and the like. Ideally, the ozone should be produced in small quantities to enrich the atmosphere with this gas. Ozone is a tertiary oxygen molecule, and is highly unstable. It exists only for a matter of minutes before decaying back to the stable binary state. Thus, it must be produced continuously when and where needed to be effective.
The most convenient and safest means to produce ozone is with ultraviolet radiation. Ultraviolet light, usually from a discharge tube, has a wavelength selected such that its photon energy corresponds to the energy needed to change normal binary oxygen O.sub.2 to ozone O.sub.3.
Unfortunately, the ultraviolet wavelengths used for ozone production are also dangerous to humans and animals, and can cause skin or eye damage. This light, being invisible, gives no warning to humans in the vicinity. For this reason, ultraviolet or UV ozone generators are usually provided with shields and baffles to prevent the radiation from leaking out of the machine. However, these structures also tend to obstruct air flow and reduce the efficiency of the machine.
Where ozone is desired to control food decay bacteria or fungus in a cold locker, cooler, or other food storage compartment, an ultraviolet source is usually provided with baffling which may prevent danger to humans. However, little or no thought is given to preventing the radiation from falling on meat or vegetables. Consequently, damage to the quality of the food can occur resulting in degradation in color and taste.
The control over ozone output of a conventional UV device is exercised by masking off a portion of the UV lamp or generating table using either a sleeve or a shield member over the lamp or tube. With this structure, adjustment is cumbersome and time consuming, and in effect denies the user any real control over the output.